;/* | |
; * FreeRTOS Kernel V10.3.0 | |
; * Copyright (C) 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved. | |
; * | |
; * Permission is hereby granted, free of charge, to any person obtaining a copy of | |
; * this software and associated documentation files (the "Software"), to deal in | |
; * the Software without restriction, including without limitation the rights to | |
; * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of | |
; * the Software, and to permit persons to whom the Software is furnished to do so, | |
; * subject to the following conditions: | |
; * | |
; * The above copyright notice and this permission notice shall be included in all | |
; * copies or substantial portions of the Software. | |
; * | |
; * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR | |
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; * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN | |
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; * http://www.FreeRTOS.org | |
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; * | |
; * 1 tab == 4 spaces! | |
; */ | |
EXTERN pxCurrentTCB | |
EXTERN ulCriticalNesting | |
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; Context save and restore macro definitions | |
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; | |
portSAVE_CONTEXT MACRO | |
; Push R0 as we are going to use the register. | |
STMDB SP!, {R0} | |
; Set R0 to point to the task stack pointer. | |
STMDB SP, {SP}^ | |
NOP | |
SUB SP, SP, #4 | |
LDMIA SP!, {R0} | |
; Push the return address onto the stack. | |
STMDB R0!, {LR} | |
; Now we have saved LR we can use it instead of R0. | |
MOV LR, R0 | |
; Pop R0 so we can save it onto the system mode stack. | |
LDMIA SP!, {R0} | |
; Push all the system mode registers onto the task stack. | |
STMDB LR, {R0-LR}^ | |
NOP | |
SUB LR, LR, #60 | |
; Push the SPSR onto the task stack. | |
MRS R0, SPSR | |
STMDB LR!, {R0} | |
LDR R0, =ulCriticalNesting | |
LDR R0, [R0] | |
STMDB LR!, {R0} | |
; Store the new top of stack for the task. | |
LDR R1, =pxCurrentTCB | |
LDR R0, [R1] | |
STR LR, [R0] | |
ENDM | |
portRESTORE_CONTEXT MACRO | |
; Set the LR to the task stack. | |
LDR R1, =pxCurrentTCB | |
LDR R0, [R1] | |
LDR LR, [R0] | |
; The critical nesting depth is the first item on the stack. | |
; Load it into the ulCriticalNesting variable. | |
LDR R0, =ulCriticalNesting | |
LDMFD LR!, {R1} | |
STR R1, [R0] | |
; Get the SPSR from the stack. | |
LDMFD LR!, {R0} | |
MSR SPSR_cxsf, R0 | |
; Restore all system mode registers for the task. | |
LDMFD LR, {R0-R14}^ | |
NOP | |
; Restore the return address. | |
LDR LR, [LR, #+60] | |
; And return - correcting the offset in the LR to obtain the | |
; correct address. | |
SUBS PC, LR, #4 | |
ENDM | |